1. Field of the Invention
The invention relates to a control system for at least one electric motor, usable as a generator, of a vehicle, and also relates to a braking system for a vehicle.
2. Description of the Related Art
FIG. 1 is a schematic depiction to explain a manner of operation of a conventional braking system of a hybrid vehicle or electric vehicle.
The conventional braking system schematically reproduced in FIG. 1 is installed nowadays in a variety of hybrid vehicles (for example in a Mercedes S-class hybrid or a BMW 5-series hybrid). The conventional braking system has an electric motor 10 usable as a generator. Control can be applied to electric motor 10, by way of a microcontroller 12 and an inverter controller 14, in such a way that a generator braking torque Mgen can be exerted by way of electric motor 10 on at least one wheel 16 of the vehicle equipped with the conventional braking system, or on at least one of its vehicle axles.
Microcontroller 12 defines a target braking torque variable Mgen0 corresponding to the generator braking torque Mgen, the target braking torque variable Mgen0 being defined in consideration of a furnished specification signal 18 with regard to a driver-requested braking input and of at least one furnished wheel rotation speed signal 20 with regard to at least one wheel rotation speed of the at least one wheel 16 of the vehicle. Microcontroller 12 then outputs to inverter controller 14 the target braking torque variable Mgen0 that has been defined. Inverter controller 14 then applies control to electric motor 10 by way of a control signal 22 in accordance with the previously defined target braking torque variable Mgen0. (In the conventional braking system of FIG. 1, the specification signal 18 is furnished to microcontroller 12 by a pedal travel sensor 26 linked to a brake pedal 24 of the braking system.)
Microcontroller 12 and inverter controller 14 are supplied with a battery voltage UB from a vehicle battery 28. Electric motor 10, on the other hand, is supplied with a high voltage UHV from a vehicle-internal high-voltage source 30.